Introduction to ARP Poison Routing——ARP欺骗

On an Ethernet/IP network when Host-A wants to send a packet to Host-B it needs to know the Host-B MAC address(MAC-B) in order to communicate.Host-A will ask for MAC-B with an ARP request packet sent in broadcast(FFFFFFFFFFFF).Only the machine with the specified IP address(Host-B) will answer to this request with an ARP Reply packet sent back in unicast directly to the Host-A Mac address(MAC-A).At this point Host-A will send IP packets with destination IP-B using MAC-B as destination address in the Ethernet frame.ARP Request and Reply packets are sent only if the Host does'nt know the Mac address of the target machine;Once learned the ARP Cache will be used.

　　Example:(Host-A wants to talk to Host-B)

　　1)Host-A -> check the ARP Cache if IP-B/MAC-B mapping exist

　　2)Host-A -> ARP Request – What is the MAC address associated with IP-B?

　　3)Host-B -> ARP Reply – My MAC address is MAC-B and my ip address IP-B

　　4)Host-A -> Update the ARP Cache and sends packets to IP-B using MAC-B

　　Flash演示下载　　

　attachment/month_0604/e2006426165548.swf